Propagation News – 24 May 2020

| May 22, 2020

Last week was dominated by extensive sporadic E openings that made 10 metres sound like 20 metres on a good day. The openings were steady and stable, with lots of stations around Europe being very workable. These openings extended to multi-hop as well, with Chris, VO1CH being heard on 10m FT8 at 1240UTC on Monday, the 18th, for example. Low-power beacons have also been heard—the IW4EIR beacon, running just 1.5W, was heard on 28.195MHz at 1600UTC on Monday as well.

If you are interested in monitoring 10m beacons, Martin, G3USF has updated his 10 metre beacon list.

Hopefully, the sporadic E season will continue to improve over the next few weeks. Other than sporadic E, HF conditions have been average for this time of year. Late spring and summer are traditionally times when maximum usable frequencies (MUF) decline during the day due to a change in ionospheric chemistry. However, the good news is that night-time MUFs are higher, with bands like 20 metres remaining open long after sunset if there is sufficient ionisation.

The Sun remains very quiet. Two lighter plage areas—bright regions in the Sun’s chromosphere—have moved into view, but are unlikely to turn into sunspots. As a result NOAA predicts the solar flux index will remain around 70. It also predicts that the Sun will remain stable geomagnetically, bringing a maximum Kp index of two. So it looks like sporadic E will continue to provide the HF fun on the higher HF bands.

VHF and up

Most of next week will be dominated by high pressure just south of the UK and hence tropo will be a good mode to try. At this time of the year, the strong sunshine makes any nocturnal enhancement of conditions temporary and soon disappears after sunrise and the new thermals destroy the night-time cooling inversion.

However, the main high pressure subsidence inversion is a different case and extends across the same region as the area of high pressure and will be present throughout. This will mean paths across the North Sea, English Channel or Bay of Biscay should do well. Unlike sporadic E, tropo contacts need not be rushed.

A fairly strong Atlantic jet stream will push across the UK this weekend and when it reaches the near continent it will be in a good place for sporadic E in a broad direction range from Scandinavia, round through the Balkans, to Italy and Spain.

Meanwhile, the Atlantic will continue to provide jet stream segments for openings across the pond. The association of sporadic E with jet streams is useful, since the charts show the meandering jet stream extending well east over Russia and could be used for paths to the Far East.

There is a hint that a region of showers may develop around the middle of next week to give an opportunity for some GHz rain scatter propagation.

The Moon’s reaches peak declination on Tuesday and path losses are falling all week. 144MHz sky noise is low.

A number of small showers keep May and June an active time for meteor scatter operations, so keep looking for early morning opportunities before the sporadic E.

Category: GB2RS Propagation News